de Juan Carlos, Calbet Albert, Saiz Enric
Department of Marine Biology and Oceanography, Institut de Ciències del Mar (ICM), CSIC Pg. Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain.
J Plankton Res. 2023 Sep 6;45(5):751-762. doi: 10.1093/plankt/fbad037. eCollection 2023 Sep-Oct.
The study of a species' thermal tolerance and vital rates responses provides useful metrics to characterize its vulnerability to ocean warming. Under prolonged thermal stress, plastic and adaptive processes can adjust the physiology of organisms. Yet it is uncertain whether the species can expand their upper thermal limits to cope with rapid and extreme changes in environmental temperature. In this study, we reared the marine copepod at control (19°C) and warmer conditions (25°C) for >18 generations and assessed their survival and fecundity under short-term exposure to a range of temperatures (11-34°C). After multigenerational warming, the upper tolerance to acute exposure (24 h) increased by 1-1.3°C, although this enhancement decreased to 0.3-0.8°C after longer thermal stress (7 days). Warm-reared copepods were smaller and produced significantly fewer offspring at the optimum temperature. No shift in the thermal breadth of the reproductive response was observed. Yet the fecundity rates of the warm-reared copepods in the upper thermal range were up to 21-fold higher than the control. Our results show that chronic warming improved tolerance to stress temperatures and fecundity of , therefore, enhancing its chances to persist under extreme heat events.
对一个物种的热耐受性和生命率反应的研究提供了有用的指标，以表征其对海洋变暖的脆弱性。在长期热应激下，可塑性和适应性过程可以调节生物体的生理机能。然而，该物种是否能够扩大其热上限以应对环境温度的快速和极端变化尚不确定。在本研究中，我们将海洋桡足类动物在对照温度（19°C）和较高温度（25°C）下饲养超过18代，并评估它们在短期暴露于一系列温度（11-34°C）下的存活率和繁殖力。经过多代变暖后，对急性暴露（24小时）的热耐受性上限提高了1-1.3°C，尽管在更长时间的热应激（7天）后，这种提高降至0.3-0.8°C。在温暖环境中饲养的桡足类动物体型较小，在最适温度下产生的后代明显较少。未观察到生殖反应的热宽度发生变化。然而，在较高温度范围内，温暖环境中饲养的桡足类动物的繁殖率比对照组高出21倍。我们的结果表明，长期变暖提高了耐受性和繁殖力，因此增加了其在极端高温事件下生存的机会。
